| 1. |
- Agthe, Michael, et al.
(författare)
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Controlling orientational and translational order of iron oxide nanocubes by assembly in nanofluidic containers
- 2015
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 31:45, s. 12537-12543
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that spatial confinement can be used to control the orientational and translational order of cubic nanoparticles. For this purpose we have combined X-ray scattering and scanning electron microscopy to study the ordering of iron oxide nanocubes that have self-assembled from toluene-based dispersions in nanofluidic channels. An analysis of scattering vector components with directions parallel and perpendicular to the slit walls shows that the confining walls induce a preferential parallel alignment of the nanocube (100) faces. Moreover, slit wall separations that are commensurate with an integer multiple of the edge length of the oleic acid-capped nanocubes result in a more pronounced translational order of the self-assembled arrays compared to incommensurate confinement. These results show that the confined assembly of anisotropic nanocrystals is a promising route to nanoscale devices with tunable anisotropic properties.
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| 2. |
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| 3. |
- Arboled, C., et al.
(författare)
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Assessing lesion malignancy by scanning small-angle x-ray scattering of breast tissue with microcalcifications
- 2019
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 64:15
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Tidskriftsartikel (refereegranskat)abstract
- Scanning small-angle x-ray scattering (SAXS) measurements were performed on 36 formalin-fixed breast tissue biopsies obtained from two patients. All samples contained microcalcifications of type II, i.e. formed by hydroxyapatite. We demonstrate the feasibility of classifying breast lesions by scanning SAXS of tissues containing microcalcifications with a resolution of 35 mu m x 30 mu m We report a characteristic Bragg peak found around q = 1.725 nm(-1) that occurs primarily for malignant lesions. Such a clear SAXS fingerprint is potentially linked to structural changes of breast tissue and corresponds to dimensions of about 3.7 nm. This material property could be used as an early indicator of malignancy development, as it is readily assessed by SAXS. If this fingerprint is combined with other known SAXS features, which also indicate the level of malignancy, such as lipid spacing and collagen periodicity, it could complement traditional pathology-based analyses. To confirm the SAXS-based classification, a histopathological workup and a gold standard histopathological diagnosis were conducted to determine the malignancy level of the lesions. Our aim is to report this SAXS fingerprint, which is clearly related to malignant breast lesions. However, any further conclusion based on our dataset is limited by the low number of patients and samples. Running a broad study to increase the number of samples and patients is of great importance and relevance for the breast-imaging community.
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| 4. |
- Björn, Linnea, 1994, et al.
(författare)
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Process-Induced Structures of Injection-Molded High-Density Polyethylene─Combining X-ray Scattering and Finite Element Modeling
- 2024
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Ingår i: ACS Applied Polymer Materials. - 2637-6105. ; 6:8, s. 4852-4864
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Tidskriftsartikel (refereegranskat)abstract
- The success of plastics heavily relies on fast melt processing methods used for large-scale industrial manufacturing, including injection molding. The hierarchical structure of the solid polymer depends on material selection combined with processing conditions, making mechanical properties of the injection molded part difficult to predict. Here we show how scanning small- and wide-angle X-ray scattering, birefringence microscopy, and polarized light optical microscopy can be combined with injection molding simulations to shed light on the correlation between the polymer morphology of high-density polyethylene and processing conditions. The scattering data revealed that the complex layered structure highly depends on the pressure during the holding phase of injection molding. Furthermore, we identified specific work of flow as a main parameter to capture the changes in morphology induced by varying the process settings. Overall, a good agreement was found between experimental data and the computational simulations, suggesting that computational simulations can be further used to predict the multiphase morphology of injection molded parts.
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| 5. |
- Björn, Linnea, 1994, et al.
(författare)
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Scanning Small-Angle X-ray Scattering of Injection-Molded Polymers: Anisotropic Structure and Mechanical Properties of Low-Density Polyethylene
- 2023
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Ingår i: ACS Applied Polymer Materials. - 2637-6105. ; 5:8, s. 6429-6440
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Tidskriftsartikel (refereegranskat)abstract
- Injection molding is known to create a layered anisotropicmorphologyacross the sample thickness due to varying shear and cooling ratesduring the manufacturing process. In this study, scanning small-angleX-ray scattering was used to visualize and quantify the distributionof hierarchical structures present in injection-molded parts of low-densitypolyethylene (LDPE) with varying viscosities. By combining scatteringdata with results from injection molding simulations and tensile testing,we find that oriented shish-kebab structures, as well as elongatedspherulite structures consisting of semicrystalline ellipsoids, contributeto high ultimate tensile strength along the flow direction. Furthermore,we show that a higher degree of orientation is found close to theinjection gate and in LDPE with higher viscosity, consequently fromelevated shear and cooling rates present during the injection moldingprocess.
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| 6. |
- Casanova, Elisa A., et al.
(författare)
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SAXS imaging reveals optimized osseointegration properties of bioengineered oriented 3D-PLGA/aCaP scaffolds in a critical size bone defect model
- 2023
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Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 294
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Tidskriftsartikel (refereegranskat)abstract
- Healing large bone defects remains challenging in orthopedic surgery and is often associated with poor outcomes and complications. A major issue with bioengineered constructs is achieving a continuous interface between host bone and graft to enhance biological processes and mechanical stability. In this study, we have developed a new bioengineering strategy to produce oriented biocompatible 3D PLGA/aCaP nanocomposites with enhanced osseointegration. Decellularized scaffolds -containing only extracellular matrix- or scaffolds seeded with adipose-derived mesenchymal stromal cells were tested in a mouse model for critical size bone defects. In parallel to micro-CT analysis, SAXS tensor tomography and 2D scanning SAXS were employed to determine the 3D arrangement and nanostructure within the critical-sized bone. Both newly developed scaffold types, seeded with cells or decellularized, showed high osseointegration, higher bone quality, increased alignment of collagen fibers and optimal alignment and size of hydroxyapatite minerals.
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| 7. |
- Conceição, Andre L.C., et al.
(författare)
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Unveiling breast cancer metastasis through an advanced X-ray imaging approach
- 2024
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Ingår i: Scientific Reports. - 2045-2322 .- 2045-2322. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Breast cancer is a significant global health burden, causing a substantial number of deaths. Systemic metastatic tumour cell dissemination is a major cause of poor outcomes. Understanding the mechanisms underlying metastasis is crucial for effective interventions. Changes in the extracellular matrix play a pivotal role in breast cancer metastasis. In this work, we present an advanced multimodal X-ray computed tomography, by combining Small-angle X-ray Scattering Tensor Tomography (SAXS-TT) and X-ray Fluorescence Computed Tomography (XRF-CT). This approach likely brings out valuable information about the breast cancer metastasis cascade. Initial results from its application on a breast cancer specimen reveal the collective influence of key molecules in the metastatic mechanism, identifying a strong correlation between zinc accumulation (associated with matrix metalloproteinases MMPs) and highly oriented collagen. MMPs trigger collagen alignment, facilitating breast cancer cell intravasation, while iron accumulation, linked to angiogenesis and vascular endothelial growth factor VEGF, supports cell proliferation and metastasis. Therefore, these findings highlight the potential of the advanced multimodal X-ray computed tomography approach and pave the way for in-depth investigation of breast cancer metastasis, which may guide the development of novel therapeutic approaches and enable personalised treatment strategies, ultimately improving patient outcomes in breast cancer management.
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| 8. |
- Corona, Patrick T., et al.
(författare)
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Fingerprinting soft material nanostructure response to complex flow histories
- 2022
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Ingår i: Physical Review Materials. - 2475-9953. ; 6:4
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the complex connection between flow-processing history, fluid structure, and fluid properties represents a grand challenge for the engineering and fundamental study of nanostructured soft materials. To address this challenge, we report measurements using scanning small-angle x-ray scattering in a fluidic four-roll mill (FFoRM), which enables rapid nanostructural characterization of complex fluids under an unprecedentedly diverse range of flow histories. Combining this technique with analysis of the Lagrangian deformation history of fluid elements, we demonstrate rapid mapping of orientational ordering of fluids' nanostructure along diverse deformation trajectories that emulate those encountered in flow processing. Using demonstrative experiments on model rodlike nanoparticle dispersions, we show that differences in rod flexibility and rod-rod interactions play a significant role in determining the fluid's anisotropic structural response to similar flow histories. An analysis of the coupling between measured particle alignment and interparticle correlations reveals these differences to arise from the nature and strength of interparticle interactions in flow. These measurement and analysis techniques produce large datasets that hold promise toward advancing process-structure-property models and inverse design processes of flows that are tailored to produce targeted nanostructures.
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| 9. |
- Darmadi, Iwan, 1990, et al.
(författare)
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Bulk-Processed Pd Nanocube-Poly(methyl methacrylate) Nanocomposites as Plasmonic Plastics for Hydrogen Sensing
- 2020
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Ingår i: ACS Applied Nano Materials. - : American Chemical Society (ACS). - 2574-0970. ; 3:8, s. 8438-8445
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Tidskriftsartikel (refereegranskat)abstract
- Nanoplasmonic hydrogen sensors are predicted to play a key role in safety systems of the emerging hydrogen economy. Pd nanoparticles are the active material of choice for sensor prototype development due to their ability to form a hydride at ambient conditions, which creates the optical contrast. Here, we introduce plasmonic hydrogen sensors made from a thermoplastic nanocomposite material, that is, a bulk material that can be molded with standard plastic processing techniques, such as extrusion and three-dimensional (3D) printing, while at the same time being functionalized at the nanoscale. Specifically, our plasmonic plastic is composed of hydrogensensitive and plasmonically active Pd nanocubes mixed with a poly(methyl methacrylate) matrix, and we optimize it by characterization from the atomic to the macroscopic level. We demonstrate meltprocessed deactivation-resistant plasmonic hydrogen sensors, which retain full functionality even after SO weeks. From a wider perspective, we advertise plasmonic plastic nanocomposite materials for application in a multitude of active plasmonic technologies since they provide efficient scalable processing and almost endless functional material design opportunities via tailored polymer- colloidal nanocrystal combinations.
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| 10. |
- Gao, Zirui, et al.
(författare)
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High-speed tensor tomography: iterative reconstruction tensor tomography (IRTT) algorithm
- 2019
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Ingår i: Acta Crystallographica Section A: Foundations and Advances. - 2053-2733. ; 75, s. 223-238
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Tidskriftsartikel (refereegranskat)abstract
- The recent advent of tensor tomography techniques has enabled tomographic investigations of the 3D nanostructure organization of biological and material science samples. These techniques extended the concept of conventional X-ray tomography by reconstructing not only a scalar value such as the attenuation coefficient per voxel, but also a set of parameters that capture the local anisotropy of nanostructures within every voxel of the sample. Tensor tomography data sets are intrinsically large as each pixel of a conventional X-ray projection is substituted by a scattering pattern, and projections have to be recorded at different sample angular orientations with several tilts of the rotation axis with respect to the X-ray propagation direction. Currently available reconstruction approaches for such large data sets are computationally expensive. Here, a novel, fast reconstruction algorithm, named iterative reconstruction tensor tomography (IRTT), is presented to simplify and accelerate tensor tomography reconstructions. IRTT is based on a second-rank tensor model to describe the anisotropy of the nanostructure in every voxel and on an iterative error backpropagation reconstruction algorithm to achieve high convergence speed. The feasibility and accuracy of IRTT are demonstrated by reconstructing the nanostructure anisotropy of three samples: a carbon fiber knot, a human bone trabecula specimen and a fixed mouse brain. Results and reconstruction speed were compared with those obtained by the small-angle scattering tensor tomography (SASTT) reconstruction method introduced by Liebi et al. [Nature (2015), 527, 349–352]. The principal orientation of the nanostructure within each voxel revealed a high level of agreement between the two methods. Yet, for identical data sets and computer hardware used, IRTT was shown to be more than an order of magnitude faster. IRTT was found to yield robust results, it does not require prior knowledge of the sample for initializing parameters, and can be used in cases where simple anisotropy metrics are sufficient, i.e. the tensor approximation adequately captures the level of anisotropy and the dominant orientation within a voxel. In addition, by greatly accelerating the reconstruction, IRTT is particularly suitable for handling large tomographic data sets of samples with internal structure or as a real-time analysis tool during the experiment for online feedback during data acquisition. Alternatively, the IRTT results might be used as an initial guess for models capturing a higher complexity of structural anisotropy such as spherical harmonics based SASTT in Liebi et al. (2015), improving both overall convergence speed and robustness of the reconstruction.
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